Field of the Invention
The present invention relates to mobile communication.
Discussion of the Related Art
3GPP (3rd Generation Partnership Project) LTE (Long Term Evolution) that is an advancement of UMTS (Universal Mobile Telecommunication System) is being introduced with 3GPP release 8. The 3GPP LTE uses orthogonal frequency division multiple access (OFDMA) in a downlink and uses single carrier-frequency division multiple access (SC-FDMA) in an uplink. The 3GPP LTE adopts MIMO (multiple input multiple output) having maximum four antennas. Recently, a discussion of 3GPP LTE-A (LTE-Advanced) which is the evolution of the 3GPP LTE is in progress.
As set forth in 3GPP TS 36.211 V10.4.0, the physical channels in 3GPP LTE may be classified into data channels such as PDSCH (physical downlink shared channel) and PUSCH (physical uplink shared channel) and control channels such as PDCCH (physical downlink control channel), PCFICH (physical control format indicator channel), PHICH (physical hybrid-ARQ indicator channel) and PUCCH (physical uplink control channel).
Meanwhile, in a next-generation mobile communication system, it is anticipated that a small cell having small cell coverage will be added into coverage of a macro cell.
Furthermore, it is anticipated that user equipment (UE) or a terminal can be dually connected to both the small cell and the macro cell through a carrier aggregation technique in the next-generation mobile communication system.
Meanwhile, in recent years, research into communication between devices or the device and a server without human interaction, that is, without human intervention, that is, machine type communication (MTC) has been actively conducted. The MTC represents a concept in which not a terminal used by human but a machine performs communication by using the existing wireless communication network.
However, the MTC device will not have a low capability, for example, a carrier aggregation (CA) function in order to increase a supply rate with low cost. In this case, there is a problem that the MTC device cannot be dually connected to both the small cell and the macro cell.